The pigments active in photosynthesis of the cryptomonad algae will be investigated. Two general types of chromoprotein to be studied are the biliproteins (phycocyanin and phycoerythrin) and chlorophyll (a or c2)-protein complexes, and certain spectroscopic experiments on chlorophyll c2 itself will be carried out. Particular emphasis will be placed on the isolation and characterization of a chlorophyll c2-protein complex since none have so far been obtained from any organism. Cryptomonad biliproteins will also be examined as purified entities, particularly in regard to the properties of the separated polypeptides and with respect to the critical testing of proposed mechanisms of the excitation energy transfer characteristic of the cryptomonads. Information on energy migration among the various components in the thylakoid may be obtained for these systems. The possible role of chlorophyll c2 as an intermediate in energy transfer from biliprotein to reaction center will receive major attention and is the principal target of the studies involving whole cells.